Slide fastener manufacture



June 25, 1957 J. G. SOAVE 2,796,649

SLIDE FASTENER MANUFACTURE Filed Oct. 20, 1953 INVENTOR JOHN G. 30 AVEATTORNEY Uireci rate Patented June 25, 1957 ice 2,796,649 SLIDE FASTENERMANUFAC John G. Suave, Long Island City, N. Y., assignor to WaldesKohinoor, Inc., Long Island City, N. Y., a corporation of New YorkApplication October 20, 1953, Serial No. 387,295 7 Claims. (Cl.24-2il5.16)

This invention relates to improvements in slide fastener manufacture,and more particularly to an improved method of forming the stringers ofslide fasteners and to slide fastener stringers produced thereby.

As is well known, a slide fastener or so-called zipper is made in partof two oppositely arranged stringers, each consisting of a tape providedalong one longitudinal side edge, usually termed the front edge, with abead to which the slide fastener elements are clamped and having anopposite or rear edge portion which is adapted to be secured to thecorresponding edge of a garment or article opening for. which the slidefastener providesa closure, usually by sewing. ,The clamping of thefastener elements to the front edge head of the tape results in theinitially straight tape becoming slightly convex in lengthwisedirection, with the convexity being in the direction of its beaded edge,since the clamping of elements to tape bead causes the latter toflatten, and hence to become longer than therear edge portion of thetape. Consequently, fastener elements carried by the tape. bead assume aradial position in which their coupling ends or heads are spaced fromeachtother slightly more than the leg portions which clampingly embracethe bead. Obviously, such is detrimental to the accurate meshing of thefastener elements of one stringer with the corresponding elements of theopposite stringer Recognizing this condition, it has therefore becomestandard practice in the trade to impart to the-tape, by stretching orotherwise elongating its rear edge portion, curvature opposite to thatimparted by application'of the fastener elements to the beaded edgethereof as aforesaid. Such procedure results in the tape having aninitially concave curvature designed to compensate for the oppositeor'convex curvature subsequently imparted by the attachment of thefastener elements, with the result that the completed stringer, beforeit is sewn to the garment or article, is substantially straight.

However, it was found that this expedient makes no provision for theknown fact that the stringer tape is distorted'when it is sewn to thegarment or article along its rear edge. Consequent to this sewingoperation, the tape contracts lengthwise in its rear edge zone, so thatit again becomes shorter in its rear zone than in its front or beadedzone, with the result that, following sewing, the front edge or beadedzone has irregular wavy form which is likely to impair the smooth andeasy operation of the fastener slider.

While numerous attempts have been directed to the solution of thisproblem, such have not been successful. For example, it does not sufliceinitially to shorten the beaded front edge zone of the stringer tapewith respect to its rear edge, as by sewing the bead cord to the frontedge under tension, so that the bead will shorten when the tension isrelieved, thus giving the tape an initially concave curvature. Whilesuch a procedure compensates, after a fashion, for the lengthening ofthe tape along its beaded edge caused by attaching the fastenerelements, it does not counteract the additional convexity causing theirregular waves to be produced along the frontedge of the tape asresults fiom the stitching operation. Moreover, it was found to beexceedingly diflicult to control the lengthening of the rear edge byshortening the front edge of the tape to the exact limits required toobtain a tape devoid of irregular waves following sewing thereof to thegarment or article.

Accordingly, a major objectof the present invention is to provide aworkable and extremely practical method by which a stringer may belengthened throughout its rear or attaching zone so as to compensate forthe shortening of the tape throughout such zone as results from sewingthe tape to the garment or article.

Another object of the invention is the provision of a method for formingin a stringer tape a multiplicity of small regular waves or undulationsextending transversely inward from the rear edge. thereof, and whichgive a controlled lengthening of the tape in its rear or attaching zone.

A further object of the invention is the provision of a method foreffecting a controlled lengthening of the tape of a fastener stringeralong its rear edge ,zone, as compared to its front edge zone, whichlengthening is such as not only to compensate for the convexity'impartedto the tape in clamping of the fastener elements to its edge bead, butalso to counteract for shortening of the tape along its rear edge zoneor portion consequent tothe sewing of the tape to the garment orarticle.

Yet another object of the invention is die provision of a method oftreating slide fastener stringers during the course of their manufacturein such a way as to produce a stringer which is generally straightfollowing final sew ing thereof to a garment or article, and which isfurther characterized by the fact that its fastener elements areuniformly spaced from one another throughout their full lengths. V V

Another important object of the invention is the pro vision of stringertapes for slide fastener or so-called zipper closures chaarcterized inthat their rear or attaching edge zones are provided with a multiplicityof small regular wavy undulations which extend transversely in ward fromthe rear edge of said tapes, and which are of depth and number as tocompensate for the relative shortening or contraction of said rear edgezone consequent to the attachment of the fastener elements to the frontbeaded edge of the tapes and/or to the stringers being sewn to anarticle or garment; I

Another object of'the invention is the provision of'slide fastenerstringers'whose rear edge attaching zones are crimped in such a way asto effect lengthening thereof as compared to their front edge zones byan amount as to compensate for the lengthwise contraction of said rearzones resulting from the sewing of the tapes to the edges of a garmentor article opening;

The above and other objects and advantages'of the invention will beclear from the following detailed description, taken with theaccompanying drawings, wherein,

Figure 1 is a fragmentary plan view showing a length of the initiallystraight stringer tape before the fastener elements are afiixed thereto;

Fig. 2 is a similar View of the same stringer tape following attachmentof the fastener elements to its beaded edge;

its rear edge zone is effected according to the invention; Fig. 4 isillustrative of another tool by which the tape may be controllablycrimped or regularly undulated' along its rear edge zone;

Fig. Sillustrates the stringer tape-shown in Fig. 2 following completionof the crimping operation; and Fig. 6 is a view similar to Fig. 5 butillustrating the Fig. 3 is a section through one form of crimping dieortool by which crimping or waving of the tape along.

3 a completed stringer following its attachment to the garment orarticle.

Referring to the drawings, reference numeral 10 designatesaconventionaltape as used in the manufacture of slide .fastenersio'r-'so-calledzipper'sl. .Such atape is provided at its longitudinal frontedge zone orport ion 12a .with a bead 11' .to'which thefastener elementsare to be attached andlwith a' rear edgefzone l2 which is adapted to besecured 'to a garment orother article, usuallybysewing.

- Fig. 2 is illustrative of the tape shown in Fig. 1 followingattachment of the fastener elements 13 thereto as by clamping their legportions to the tape bead '11. Asexplained in the foregoing, suchclamping causes the tape bead 11 to flatten under the clamping pressureapplied thereto by the fastener elements and thereby to lengthen. Thislengtheningof-thebeadimparts convex curvature to the complete stringer,the convexity being in the direction of its front or beaded edge. Due tothis convex curvature, the'fastener elements 13, instead of beingparallel to and uniformly spaced from one another throughout their fulllengths, assume an inclined position accord ing to which their couplingheads 14 are'spaced farther from each other than are their leg portions15 which attach to the tape bead. If such a stringer is now sewn to anarticle, the convexity thereof is liable to be increased, due to thefact that the sewing operation results in further shortening of thealready shorter rear edge zone of the tape.

According to the present invention, not only the aforesaid convexity ofthe stringer resulting from attachment of the fastener elements asaforesaid, but also the further shortening of the rear edge zone of thestringer tape occurring when the latter is sewn to the garment orarticle, is overcome in workable and practical manner by a controlledlengthening of the stringer tapealong its rear edge zone, preferablyfollowing attachment of the fastener elements thereto, as aforesaid.Such result is simply efiected by imparting a multiplicity of smallregular wavy indentations in the rear or attaching zone of the tape andwhich extend inwardly from its rear edge, as by crimping the tape alongsaid rear e'dge.

Referring to Fig. 3, such crimping of the tape as aforesaid may beeifected in a crimping die consisting of two rack-like parts 16 and 17whose respective teeth 18 and 19 intermesh with one another. Thus, thetape is exposed at regular short-length intervals to the opposingpressures of the intermeshing teeth 18, 19, such resultingin amultiplicity of small, regular wavy undulations 20 being imparted to thetape and which extend transversely inward a short distance from its rearedge. Upon release of the crimping pressure imparted by the racklikeparts 16, 17, the waves or undulations 20 tend to flatten slightly, andhence the rear edge zone of the stringer tape lengthens by a smallamount, as compared to its front or element-carrying edge. It isalso'possible to crimp the rear edge zone 12 of the stringer tape 10 byfeeding same between two rotating intermeshing gears 22, 23, asindicated in Fig. 4, such also resulting in the formation of smallregular wavy undulations 20 extending transversely inward of the tapefrom its rear edge, and a corresponding lengthening of the rear. edgezone portion as compared to the front or element-carryingedge thereof. r

As seen in Fig. 5, a stringer whose tape is Provided in its rear edgezone with crimps or small. regular undulations as aforesaid becomesslightly concaveas viewed in plan, due to its rear edge being longerthan its front edge. However, by a proper choice of the number andamplitude depth of the crimps imparted to the tape along its rear edgeas aforesaid, such lengthening of the rear edge zone of the tape ascompared to its front edge may be closely controlled, and hence may bemade such as to correspond precisely with the shortening of the tapealong its rear edge portion, which takes place when the tape is sewn tothe garment or article.

This latter highly desirable result is illustrated in Fig. 6, wherein afastener stringer having its rear edge zone crimped as aforesaid isshown to be attached by stitching 24 along its crimped rear edge at thecorresponding edge 25 of the opening provided in a garment or otherarticle. While the stitching effects shortening or contraction of therear edge zone of the tape 10, such is'less than the lengthening of saidzone imparted by the crimps or undulations 20, with the result that whenfinally se'wn, at least the front edge zone of the stringer is flatthroughout and straightway, and the fastener elements 13 are parallel toand uniformly spaced from one another throughout their full lengths.

Without further analysis, it will be seen that the presently disclosedmethod of crimping the longitudinal rear or attaching zone of a fastenerstringer tape so as to effect a controlled lengthening thereof providesthe simple solution of the problem arising from distortion of the tape,as results or can result both from attachment of the fastener elementsto its'beaded edge or from sewing of the tape along its rear edge zoneto the garment or article. Moreover, it will be seen that the hereindescribed method is' exceedingly simple in its practice, since it may becarried out merely by exposing the rear edge portion or zone of the tapeto the action of intermeshing teeth of two rack-like elements or of tworotating gears. The product of the method, namely, a stringer tapecharacterized by a transversely crimped rear edge portion, may be sewnto the garment or article just as simply as the prior stringer tapes, wiassurance that its edge which carries the fastener elements extends flatand straightway, as distinguished from extending along a curve or beingirregularly waved, and that the fastener elements are disposed parallelto and uniformly spaced from one another throughout their full length. aAlthough the method disclosed in the foregoing has been described in itsapplication to the completed stringer, that is to say, a tape to whichthe fastener elements have been applied, it may also be used toadvantage as a substitute for the process heretofore used for theinitial lengthening of the rear zone of the tape to compensate for thelengthening of the front zone resulting from attachment of the fastenerelements.

As many changes could be made in carrying out the above methods andconstructions without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe ac-' compauying drawings shall be interpreted as illustrative andnot in a limiting sense.

I claim:

1. In the manufacture of slide fastener stringers comprising a tapeadapted to carry a row of fastener elements along its front longitudinaledge zone and to be secured to a garment or article along its rearlongitudinal edge zone, the step of imparting small regular wavyundulations to the rear edge zone of the tape, said undulationsextending inwardly a small distance from the rear edge of said rear edgezone, the number and depth of said undulations being such as to rendersaid rear end zone longer than the front edge of the tape the number anddepth of said undulations being such as to render said rear edge zonelonger than the front edge of the tape by a controlled amount.

'2. In the manufacture of slide fastener stringers comprising a tapeadapted to carry a row of fastener elements along its front longitudinaledgezone and to be secured to a garment or article along its rearlongitudinal edge zone, the step of crimping the tape transversely alongits rear edge zone, the number and depth of the crimps being such as torender said rear edge zone longer than the front edge zone of the tapeby a controlled amount. e

2 3. The method of manufacturingslide fastener string-1 ers, comprisinga tape having a bead extending along its front longitudinal edge zone,said bead being adapted to carry a row of fastener elements, said tapebeing adapted to be secured to a garment or article along its rear edgezone, said method including the steps of clamping the fastener includesthe steps of clamping the fastener elements to the tape bead, andthereupon lengthening the rear edge zone of the tape an amount as tocompensate for any lengthwise distortion of the tape occurring as theresult of the clamping of the elements and/or likely to occur uponsecuring the tape along its rear edge to the garment or article.

4. The method of manufacturing slide fastener stringers comprising atape having a bead extending across its front longitudinal edge zone andcarrying a row of fastener element along said edge zone and adapted tobe secured to a garment or article along its rear edge zone, whichincludes the steps of clamping the fastener elements to the tape bead,and thereupon transversely crimping the rear edge zone of the tape, thenumber and depth of the crimps being such as to increase the length ofsaid rear edge zone by a predetermined amount compensating for anylengthwise distortion of the tape occurring as the result of theclamping of the elements and/or likely to occur upon securing the tapealong its rear edge zone to the garment or article.

5. In a slide fastener, a stringer tape having a crimped rear edge zone,the crimps extending transversely inward from said rear edge zone andbeing of number and depth as to efiect a controlled lengthening of therear edge zone of the tape with respect to the front edge zone thereof.

6. In a slide fastener, a stringer tape whose rear edge portion isprovided with a multiplicity of small regular wavy undulations extendingtransversely inward for a short distance from the rear edge portion ofthe tape, the number and depth of said undulations being such as toeffect a controlled lengthening of said rear edge portion zone of thetape with respect to its front edge portion.

'7. in a slide fastener, a stringer comprising a tape having a beadextending along its front longitudinal edge zone and a plurality offastener elements clampingly secured to said head, the rear edge zone ofthe tape being provided with a multiplicity of transverse undulationsextending inwardly for a short distance from the rear edge zone of thetape, the number and depth of said undulations being such as to effect acontrolled lengthening of the rear edge zone of the tape with respect toits front edge zone.

References Cited in the file of this patent UNITED STATES PATENTS 38,799Francis June 2, 1863 1,322,650 Sundback Nov. 25, 1919 FOREIGN PATENTS1,025,919 France 1953

